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Local stellar kinematics from HIPPARCOS data
Dehnen, Walter; Binney, James J.
From the parallaxes and proper motions of a kinematically unbiased subsample of the Hipparcos Catalogue, we have re-determined as a function of colour the kinematics of main-sequence stars. Whereas the radial and vertical components of the mean heliocentric velocity of stars show no trend with colour, the component in the direction of Galactic rot…
The Hyades: distance, structure, dynamics, and age
Brown, A. G. A.; Crifo, F.; Gomez, A. +7 more
{We use absolute trigonometric parallaxes from the Hipparcos Catalogue to determine individual distances to members of the Hyades cluster, from which the 3-dimensional structure of the cluster can be derived. Inertially-referenced proper motions are used to rediscuss distance determinations based on convergent-point analyses. A combination of para…
Nearby stars of the Galactic disk and halo
Fuhrmann, Klaus
Model atmosphere analyses of echelle spectra of some fifty nearby F- and G-type stars are presented. The sample is confined to the main-sequence, turnoff and subgiant region, regardless of the metal abundance. On the base of these data, spectroscopic parallaxes are calculated and compared to the Hipparcos astrometry to explore the reliability of t…
HIPPARCOS photometry of Herbig Ae/Be stars
de Winter, D.; van den Ancker, M. E.; Tjin A Djie, H. R. E.
The photometric behaviour of a sample of 44 Herbig Ae/Be (HAeBe) candidate stars was studied using a uniform set of optical photometry obtained by the Hipparcos mission. Astrophysical parameters (distance, temperature, luminosity, mass, age) of this sample of stars were derived as well by combining the astrometric data provided by Hipparcos with d…
ICCD Speckle Observations of Binary Stars. XIX. an Astrometric/Spectroscopic Survey of O Stars
Gies, Douglas R.; Bagnuolo, William G., Jr.; Mason, Brian D. +3 more
We present the results of a speckle interferometric survey made with the CHARA speckle camera and 4 m-class telescopes of Galactic O-type stars with V < 8. We can detect with the speckle camera binaries in the angular separation range 0.035" < rho < 1.5" with Deltam < 3, and we have discovered 15 binaries among 227 O-type systems. We c…
Distance to M31 with the Hubble Space Telescope and HIPPARCOS Red Clump Stars
Garnavich, P. M.; Stanek, K. Z.
Following the approach by Paczyński & Stanek, we compare the red clump stars with parallaxes known to better than 10% in the Hipparcos catalog with the red clump stars observed in three fields in M31 using the Hubble Space Telescope. There are ~600 and ~6300 such stars in the two data sets, respectively. The local red clump luminosity function…
The Distribution of Nearby Stars in Velocity Space Inferred from HIPPARCOS Data
Dehnen, Walter
The velocity distribution f(v) of nearby stars is estimated, via a maximum likelihood algorithm, from the positions and tangential velocities of a kinematically unbiased sample of 14,369 stars observed by the Hipparcos satellite. The distribution f shows rich structure in the radial and azimuthal motions, v_R and v_phi, but not in the vertical vel…
The Age of Globular Clusters in Light of Hipparcos: Resolving the Age Problem?
Chaboyer, Brian; Demarque, P.; Kernan, Peter J. +1 more
We review five independent techniques that are used to set the distance scale to globular clusters, including subdwarf main-sequence fitting utilizing the recent Hipparcos parallax catalog. These data together all indicate that globular clusters are farther away than previously believed, implying a reduction in age estimates. We now adopt a best-f…
Interstellar reddening from the HIPPARCOS and TYCHO catalogues. I. Distances to nearby molecular clouds and star forming regions
Knude, J.; Hog, E.
The Hipparcos and Tycho Catalogues offer an interesting possibility to study the local distribution of interstellar reddening from the combination of data contained in the catalogues: Hipparcos parallaxes, Tycho B - V and spectral and luminosity classification compiled from the literature. Parallactic distances may be derived for known absorbing f…
Galactocentric Distance with the Optical Gravitational Lensing Experiment and HIPPARCOS Red Clump Stars
Paczyński, Bohdan; Stanek, Krzysztof Z.
We compare red clump stars with parallaxes known to better than 10% in the Hipparcos catalog and corrected for interstellar extinction with the OGLE red clump stars in Baade's Window, also corrected for interstellar extinction. There are ~600 and ~10,000 such stars in the two data sets, respectively. We find empirically that the average I-band mag…